I'm a coder and interested in save my eyesight. I've met the term named low blue light. Monitors decrease the level of blue color and theoretically protect my eyes. Here's a quote from monitor manufacturer Benq site

BenQ takes the eye health of users to heart and computer eye strain is no exception, offering a series of BenQ monitors designed to help everyone. Studies show that blue light from the sunlight, computer monitors and fluorescent lamps may be very harmful to the eyes causing macular degeneration or sleep disorders. These concerns are very serious and BenQ has developed a series of Eye-care monitors with features including Flicker-free and Low Blue Light technologies, so users can combat the possible side effects associated with blue light to keep eyes healthy and happy.

What do you think about low blue light technology? Is it helpful?

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    During a period of very intense computer use many years ago, I was astonished to experience eye pain which seemed to be caused by the light coming from the monitor. I found that switching to white-lettering on a black-background eliminated the pain. This was a big surprise to me, because the light from a monitor is surely less than the light outdoors. So I tried several times to go back to the normal display, but it always caused pain recurrence, and switching back to a black background always cured the pain. This was a black-and-white display. Commented Jun 27, 2015 at 19:48
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    Iron, that's interesting idea, really! But I'm asked directly about low blue light =) Commented Jun 28, 2015 at 2:19

2 Answers 2


There are two mechanisms of action how light affect humans discussed here:

  1. Amount of energy: shorter (blue) wavelengths are more energetic than lower (red), so it can be assumed that they damage photoreceptors more.
  2. Psychological: bluish light is associated with day by our biochemistry. Higher amounts of bluish light makes our brains more awake (e.g. suppressing production of melatonin)

Point 1 leaves conclusion that reducing amount of blue light from the monitor is always a good thing, while point 2 means that it's helpful as you plan to go to sleep. From my experience I can say that #2 is very true, as dim and warm light in the workplace made me sleepy and inefficient. Changing light sources to bright and cool fluorescent lights helped a lot. Also I've installed RGB led lighting in my living room and discovered that using only red light at the end of the day makes falling asleep easier. Just looking at BenQ's idea it certainly appeals to me.

However, the purpose of a monitor is to reproduce colors accurately. The question remains if the amount of blue can be reduced without affecting either color balance or just lowering brightness altogether. Modern "white" LEDs commonly used as source of light in LCD monitors are primarily blue light sources with some yellow phosphorus thrown in to balance out main emission. If BenQ used different kind of LEDs of CCFLs (less bluish) then this technology could not be turned on and off, much less adjusted. To truly limit the amount of certain component on the fly, RGB-LEDs would have to be used as backlight (they are not used here, and I'm not aware of any affordable monitor with RGB LEDs). What is presented on the video seems like simply changing color temperature to a warmer one - which is available in almost every color monitor. Even if it's not plain old color temperature, but something more sophisticated, e.g. clamp on blue channel in gamma ramp then same effect can still be achieved in software, in graphic card's gamma settings.

I disagree much with the video on the site you've linked. Even layman like me can easily point out errors:

  1. Saying that blue light is almost as bad as UV light just because it sits next to it on a spectrum is plain scaremongering. The biggest danger of UV comes from the fact that human eye can't see UV, so it won't close the iris to block it. The eye may "think" it's dark in very bright UV light and let it all in. Blue light, as part of visible spectrum, does not present this danger.
  2. The picture of blue-violet going "deep into your eye" is laughable. It shows other parts of spectrum stop at the lens while only blue reaches retina. It's plain lie, of course. Red and green do reach the retina just as well, otherwise we wouldn't be able to perceive them.

Bottom line: I think that the idea of reducing amount of blue light is good, but BenQ's execution is just a marketing gimmick or not much more in the best case.

If you really want to considerably reduce amount of blue light coming from your monitor, I recommend changing white backgrounds to yellow ones (if you work with lots of white backgrounds). This will drastically cut blue light reaching your eyes in a way not possible when still retaining impression of whiteness. Of course, eliminating large, bright areas by using dark themes (white-on-black text) will greatly cut ALL light.

If you seek to reduce strain on your eyes from monitor then I agree with statement that the biggest issue is not just the amount of light coming from the monitor. The biggest factor IMHO is the difference between monitor and it's background, that is the rest of the room. Therefore never use a computer/phone/tablet in total darkness - leave some nightlight + lower brightness to match. Also don't be afraid to crank up monitor up to 11 in a sunny day. Most monitors are set up to allow easy access to brightness and contrast adjustment - exactly for this very reason. They are meant to be used every time light in the room changes.

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    Hello, and welcome to the site! This post appears to be a very good answer, but here on Health, we strongly encourage using references. They are the only way in which we can tell if information is reliable or not. If you are struggling to find good sources, check out, What are reliable sources? If you want to learn more about our site's stance on answers without references, check out, Should answers without references be immediately deleted?
    – JohnP
    Commented Jun 30, 2015 at 17:09
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    @JohnP there are some softwares/apps that reduce the blue light from the screen automatically when sunset, help you to sleep easier, such as f.lux. They cite a lot of studies in their website.
    – Ooker
    Commented Jul 1, 2015 at 14:05
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    @Ooker - That would make a great answer, if you could review and summarize some of those studies here.
    – JohnP
    Commented Jul 1, 2015 at 14:24
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    Philips is another vendor that markets a low blue mode - calling it LowBlue Mode - however they provide little information on how it works. In the manuals, Philips states that its LowBlue Mode at level 2 matches the TÜV-Low-Blue-Light certfication. Curiously, on a Philips 499P9H, enabling blue mode 2 also increases the brightness to 100 % which is VERY bright. For my taste, with LowBlue disabled, having the brightness at 15 to 20 % is perfectly sufficient. Commented Oct 8, 2022 at 22:12

I don't have any information about whether the Benq monitor in particular will effectively reduce blue light.

But to your question... "Is it helpful?"

This article is fairly well referenced, and includes an interview with Dr Wunsch, a German light therapist. In summary, it seems long exposure to blue light from artificial sources is indeed a bad for you in both the ways mentioned by Agent_L.

The article mentions blue-blocking glasses as an alternative solution. Maybe give that a try - it'll be cheaper than a new monitor, and even the layman that Agent_L's mentions, would probably accept that blue light is reduced by wearing a filter over your eyes.

UPDATE: a partially functional archive copy of this article is now here.

  • The link seems to be broken - right now one is greeted with a banner that reads: 'Dr. Mercola's Censored Library - Take Control of Your Health' - After clicking it away there are articles linked such as 'Why Doctors Are Lying to You' and 'Executive Order Advances Biotech-Transhumanist Agenda'. Thus, it looks like the domain expired and was grabbed by some shady scammer. Commented Oct 8, 2022 at 22:17
  • @maxschlepzig For now, it's accessible partially at this archive site archive.ph/wShBy The domain didn't expire. Mercola moved his entire content over to Substack and put it behind a paywall. I've updated the answer with this link.
    – poshest
    Commented Oct 12, 2022 at 13:00
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    Mercola is not a credible source.
    – Carey Gregory
    Commented Oct 12, 2022 at 17:39
  • @CareyGregory The article was an interview with "Dr. Alexander Wunsch, a world class expert on photobiology" and most of the content sourced from him. Censor if you must, but I feel that a better approach is to let your intelligent readership decide what is useful and credible to them.
    – poshest
    Commented Oct 24, 2022 at 9:03
  • I'm not censoring anything. I simply commented that I don't find your source credible.
    – Carey Gregory
    Commented Oct 24, 2022 at 13:25

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